A campaigner whose mother died at a scandal-hit NHS hospital said the 86-year-old once collapsed on a ward after being left without her oxygen supply.

Julie Bailey set up the campaign group Cure The NHS after her mother, Bella Bailey, died at Stafford Hospital, which has been heavily criticised for putting targets and cost-cutting ahead of patient welfare.

It has been claimed that hundreds of patients died at the hospital, which is run by Mid Staffordshire NHS Foundation Trust, as a result of sub-standard treatment.

Following the death of her mother in 2007, Miss Bailey lobbied for an open investigation into how appalling standards of care were allowed to persist.

A public inquiry into the care provided by the trust between 2005 and 2009 was launched earlier this month.

Speaking at the inquiry in Stafford, Miss Bailey said patients were left “screaming out” in pain on chaotic and under-staffed wards.

She told inquiry chairman Robert Francis QC that her mother collapsed on Ward 11 of the hospital after being left in a chair with no oxygen supply because there were no nurses available to reconnect the canister.

The pensioner, who had a hiatus hernia and suffered from breathing difficulties, had left the ward to undergo an endoscopy and was placed in a chair upon her return by a hospital porter, Miss Bailey told the inquiry.

She said her niece, who had been visiting, was told repeatedly that a nurse would reconnect the oxygen supply, but after 45 minutes no nurse had arrived and her mother collapsed.

Miss Bailey said: “The healthcare assistant kept saying, ‘the nurse will be with you in a minute, the nurse will be with you in a minute’ but she never came.

“So mum collapsed and my niece telephoned me.”

She added: “I believe that if my niece hadn’t gone in to see my mum at that particular time when she collapsed then she would have died there that day. I am convinced of it.

“After that I decided that mum would never be in that hospital alone and that is what we did.”

Describing the ward, Miss Bailey said: “It was absolute chaos. There were people screaming out, shouting ‘nurse, nurse’. It was just bedlam.

“There were just relatives waiting all the way down the corridor which I later learned was people, relatives, coming in for visitor hours and then waiting to talk to staff.